transmission trouble ? - PeachParts Mercedes-Benz Forum

aufbau · #1 10-11-2003, 09:31 PM

I have a 67 300SEL which , when on the highway , seems to be reving higher than I would like. I realise this is a 4 speed tranny but is it possible that I am starting in 1st and never getting into 4th gear ?

jim16671836 · #2 10-12-2003, 04:28 PM

Many of the speedometers have dashes that are the shifting point for the transmission when you have the accellerater buried to the floor...I have a 69-280SE and it has these on the speedometer..one dash about 25 and 2 dashes about 45 and 3 dashes about 72..these are the shift points at wide open trottle..I also have them on my 300SD and it is very accurate...but you have to bury the pedal to check them...good luck

aufbau · #3 10-12-2003, 04:40 PM

I would say that it follows those check points pretty closely , my concern is the revs. I just can't see it doing 100 mph as they would be too high.

jim16671836 · #4 10-12-2003, 04:56 PM

So it is shifting to 4th..Maybe you can post the rpms while cruising at 100kph(??mph)--the book says 3245. Also shows 2 different rear end ratios..3.69 or 3.92..

psfred · #5 10-13-2003, 12:50 AM

It's gonna sound like it's over reving due to the 1:1 top gear and 3.69 or 3.92 rear end -- about 3200 or so rpm. It goes to 6600 rpm at top speed, though (115 or so mph? maybe 120). Typical of that era Benz, they make they to wind up pretty good. The W123 diesel wagons (gas ones too, I think) are the same way -- my TE runs 3000+ rpm at 65 on the highway.

Peter

#6 10-13-2003, 06:16 AM

You get to 60+ mph and it sounds like the engine want's to change gear. Well welcome to the world of the 60's benz. In which petrol was cheap so it didn't matter if you wasted heaps on the high way

Anyway. I'm converting my 250SE to manual but atm i'm still clueless and what to change the diff. Somthing below 3:96 obvisly

jim16671836 · #7 10-13-2003, 10:28 AM

Have You thought about larger Wheels & Tires...Slower on acceleration but it can be very nice cruising down the highway..

JMela · #8 10-13-2003, 11:01 AM

Assuming we have similar automatic transmission setups, with my 68 I thought the same thing and realized that 1st gear is an extra low gear (for mountains, pulling stumps, tractor pull, etc) and from a stop (with auto trans in '4th' gear these cars actually start out in 2nd gear. To utilize this low gear put your tranny in '2'.

These cars rev high at freeway speeds but that is by design. Don't worry about putting your foot down - they can take it.